Little bird? To mount it? (6)

I believe the answer is:

tomtit

I'm a little stuck... Click here to teach me more about this clue!

'little bird?' is the definition.
'tomtit' can be an answer for 'bird?' (I've seen this before). I'm not certain of the 'little' bit.

'to mount it?' is the wordplay.
'mount' becomes 'mt'.
'to'+'mt'+'it'='TOMTIT'

Can you help me to learn more?

(Other definitions for tomtit that I've seen before include "bird - with 25d" , "another bird gets both" , "Popular name for a songbird" , "Type of bird, may be blue" , "Small bird" .)

I've seen this clue in the Sydney Morning Herald.

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